1. Field of the Invention
This invention relates, generally, to telecommunications apparatus, and more particularly to a chassis for use in a coin or pay telephone.
2. Background Information
The state of the art includes various coin telephones. Some are owned and controlled by a telephone company, while others are customer owned and do not rely on signaling from a central office. Many prior art coin telephones require an independent power supply at the site of the telephone. Some sites where it may be desirable to locate a coin telephone may not have such a power supply readily accessible. The expense of providing access to such a power supply may prohibit use of such a telephone.
The prior art also includes line powered coin telephones which can obtain some of the necessary operating power from the telephone line itself. The telephone line provides at least 23 milliamperes of loop current to the telephone during the off-hook condition. During the on-hook condition, however, line loop current is limited by law to a maximum of five microamperes. Phones which require devices to be energized during on-hook condition require an additional power source, typically a battery. An example of such a system in a coin operated customer owned line powered telephone is disclosed in U.S. Pat. No. 5,133,005 to Kelley et al. Because it is customer owned, the Kelley telephone must have the ability within the telephone to rate calls, control coin collection, and connect calls rather than relying on a signal from a central office. The Kelley telephone shuts down unnecessary circuits during the on-hook condition, but has a real time clock, memory, and wake-up circuitry which must be kept energized during on-hook condition. A rechargeable battery supplies that power. The battery is charged by any excess current available from the telephone line during off-hook condition. If there is an excessively long period where the telephone remains in the on-hook condition, the battery may discharge to a low enough level to make the telephone inoperative.
Another example of a line powered telephone which uses a rechargeable battery is disclosed in U.S. Pat. No. 4,759,054 to Mellon. The Mellon phone is powered by line power in both the on-hook and off-hook condition, but it is connected to a coin trunk. Current to energize the coin collect relay is generally provided by the central office in the off-hook condition, but the phone has a battery to supply current for the coin collect in situations where the central office current is not available to operate the coin collect relay.
The owner of a coin telephone has a need to monitor its use and status to know for example, the total coins in a coin box and when repair is needed. Efficient collection routes can be designed by knowing such data. Statistical data regarding the amount of usage of a coin telephone and types of calls made from it is also useful. One such electronic system which does that is the WESROC.RTM. coin phone monitoring system. WESROC is a multipurpose monitoring system for coin telephones manufactured by Independent Technologies, Inc. of Omaha, Nebr., applicant's assignee. The WESROC apparatus and method are described in U.S. Pat. No. 5,410,590, entitled Monitoring System for Remote Devices, which was issued Apr. 25, 1995, to Blood et al. U.S. Pat. No. 5,410,590 is hereby incorporated by reference. Prior art coin telephones do not have built in capability to work with a state of the art monitoring system such as WESROC.
Public coin telephones are also subject to vandalism, and attempted fraudulent use. If a handset is shorted out, pin fraud is possible and line current can significantly increase, which could damage other components. Prior art coin telephones do not have built in capability to detect and prevent tone and pin fraud.
Accordingly, it is an object of the invention to provide a coin telephone chassis which does not need any power source other than that which is available through the telephone line. It is further object of the invention to provide a coin telephone chassis having a built-in interface for a multipurpose monitoring system for coin telephones such as WESROC. It is another object of this invention to provide a coin telephone chassis with built-in features for the WESROC monitoring system. It is another object of the invention to provide a coin telephone chassis having built-in devices to prevent tone and pin fraud.
Applicant's invention provides a coin telephone chassis which overcomes the limitations and shortcomings of prior art coin telephones.